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Ru-Chin Tu, Chun-Ju Tun, Shyi-Ming Pan, Chang-Cheng Chuo, J. K. Sheu, Ching-En Tsai,
Te-Chung Wang,and Gou-Chung Chi
IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 15, NO. 10, OCTOBER 2003
D.J. Sum

Introduction

Experiment

Results and discussion

Conclusion

References

AlGaN cap is generally placed above the
MQW to prevent electron overflow from the
active region, and to protect the InGaN active
region from the subsequent high-temperature
growth of p-type layers.
調變：
1.成長溫度
2.成長時氣體環境
Ti/Au
3.通Cp2Mg流量
TCL
P-GaN 0.2μm
P-AlGaN 30nm
MQW
5pair MQW(well2.5nm; barrier 7.5nm);
Si doped GaN barrier layer
Ti/Al
Si-doped(n-GaN) 4μm at1050℃
LT-GaN
30nm at550℃
Sapphire C face
Chip Size 300×300μm
Fig. 1. Schematic band diagram of the InGaN–GaN MQW active region with
(a) the Mg-doped AlGaN EB layer on the last InGaN quantum well and (b) on
the last GaN barrier.
Fig. 2. RT EL spectra of LEDs 7B (160 mA), 7D (20 mA), and 7F (20 mA).
The inset plots the relative output luminous intensity as a function of injection
current between 10 and 250 mA for three LEDs.
Fig. 3. Forward I–V characteristics of three LEDs. The forward voltage of
LED 7B (V = 3.63 V) exceeds that of both LEDs 7D and 7F (V = 3.25 V).
Fig. 4. RT EL spectra of LEDs 7D (20 mA), 8B (60 mA), and 9F (20 mA).
The inset plots the relative output luminous intensity as a function of injection
current between 10 and 250 mA for three LEDs.
Fig. 5. Reverse I–V characteristics of three LEDs. The leakage currents of
LEDs 7D, 8B, and 9F at a reverse bias of 5V were approximately 6 nA, 3.75 A,
and 50 nA, respectively.

The EL intensity of LEDs with LT-grown Mgdoped AlGaN layers was nearly three times larger
than that of LEDs with HT-grown AlGaN.

An Mg-doped AlGaN layer in N2 ambient grown
at LT is found to be better than that grown in the
H2 ambient due to the prevention of dissociation
and etching of the final InGaN well layer.

Ru-Chin Tu, Chun-Ju Tun, Shyi-Ming Pan, Chang-Cheng
Chuo, J. K. Sheu, Ching-En Tsai,Te-Chung Wang,and GouChung Chi “Improvement of Near-Ultraviolet InGaN–GaN
Light-Emitting Diodes With an AlGaN Electron-Blocking
Layer Grown at Low Temperature” IEEE PHOTONICS
TECHNOLOGY LETTERS, VOL. 15, NO. 10, OCTOBER
2003
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